OP, I'm not going to flame you, but I do think it would help you in terms of mental health and general self-organisation to take responsibility for your own past decisions and actions, including the erosion of the £16k, even if you feel they were dictated by others (bullying at your job) or your own poor mental health or lack of financial acumen. It sounds to me as if you might benefit from some life-coaching or brisk career/financial advice that comes from someone other than your father, because although you are presumably well into adulthood, you sound rather as if there's still quite a dependent relationship going on there. He's not emerging as any kind of villain in this, as I think you understand yourself.
Yes, I would be lying if I hadn't had twinges of unfairness at friends whose parents bought battered old houses in expensive cities in the 70s and 80s, and who, purely because of the housing market, have ended up with astonishing amounts of money in equity, and who have either already passed it onto their children by downsizing, or are poised to in some form. Other friends are comparatively cash poor now but will inherit, or have trust funds coming.
My parents are uneducated and worked in low-paid or minimum wage jobs all their working lives, and in the case of my father, repeatedly refused to be promoted to supervisor roles because he didn't like the idea, despite the fact that he had four children he could barely support to the point of there being only just about enough food at times. They have no property or savings, only a minimal pension, and live in another country.
Rather than being bequeathed money, I have been supporting them financially for most of my adult life no free GP visits in my home country, and neither is in good health and will be entirely responsible for their care home fees as they become older. I imagine lots of other people are in this position, which is pretty normal.